ios - 如何找出无色区域uibezierpath？

Question

那个灰色是 UIImageView，白色字体是 Image。

该图像放置在 UIImageView 内。

我喜欢只在字体内部着色，而不是整个 UIImageview，因为我要找出图像的坐标。

我是这种概念的新手，所以请有人指导我如何仅在图像内部着色，那里有 50 多张图像，它不是静态的，所以请给出一些好主意。

这是我用来在 UIImageView 中绘制的代码:

-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{

    UITouch *touch = [[event allTouches] anyObject];
    touchPoint = [touch locationInView:self.imgColor];

        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
        [path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];


        startingPoint=touchPoint;
        CAShapeLayer *shapeLayer = [CAShapeLayer layer];
        shapeLayer.path = [path CGPath];
        shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
        shapeLayer.lineWidth = 3.0;
        shapeLayer.fillColor = [[UIColor redColor] CGColor];
        [self.imgColor.layer addSublayer:shapeLayer];
        [arrLayer addObject:shapeLayer];

    NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);



}

Answer 1

使用这个自定义 UIImage View :

自定义 View .h

@interface CustomView : UIImageView

@end

自定义 View .m

@interface CustomView ()
{
    CGPoint touchPoint,startingPoint;
    UIView *drawingView;
}

@end


@implementation CustomView

-(void)awakeFromNib
{
    drawingView = [[UIView alloc] initWithFrame:self.bounds];
    drawingView.backgroundColor = [UIColor clearColor];
    [self addSubview:drawingView];
    [self updateMask];
}

- (void)updateMask
{
    CALayer *maskLayer = [CALayer layer];
    maskLayer.geometryFlipped = YES;
    maskLayer.contents = (id)self.image.CGImage;
    switch (self.contentMode)
    {
        case UIViewContentModeScaleToFill:
            maskLayer.contentsGravity = kCAGravityResize;
            break;
        case UIViewContentModeScaleAspectFit:
            maskLayer.contentsGravity = kCAGravityResizeAspect;
            break;
        case UIViewContentModeScaleAspectFill:
            maskLayer.contentsGravity = kCAGravityResizeAspectFill;
            break;
        case UIViewContentModeCenter:
            maskLayer.contentsGravity = kCAGravityCenter;
            break;
        case UIViewContentModeTop:
            maskLayer.contentsGravity = kCAGravityTop;
            break;
        case UIViewContentModeBottom:
            maskLayer.contentsGravity = kCAGravityBottom;
            break;
        case UIViewContentModeLeft:
            maskLayer.contentsGravity = kCAGravityLeft;
            break;
        case UIViewContentModeRight:
            maskLayer.contentsGravity = kCAGravityRight;
            break;
        case UIViewContentModeTopLeft:
            maskLayer.contentsGravity = kCAGravityTopLeft;
            break;
        case UIViewContentModeTopRight:
            maskLayer.contentsGravity = kCAGravityTopRight;
            break;
        case UIViewContentModeBottomLeft:
            maskLayer.contentsGravity = kCAGravityBottomLeft;
            break;
        case UIViewContentModeBottomRight:
            maskLayer.contentsGravity = kCAGravityBottomRight;
            break;
        default:
            break;
    }
    maskLayer.frame = drawingView.bounds;
    drawingView.layer.mask = maskLayer;
}


- (void)setImage:(UIImage *)image
{
    [super setImage:image];
    [self updateMask];
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    drawingView.frame = self.bounds;
    drawingView.layer.mask.frame = drawingView.bounds;
}


-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    touchPoint = [touch locationInView:self];

    if (!CGPointEqualToPoint(startingPoint, CGPointZero))
    {
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
        [path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];

        CAShapeLayer *shapeLayer = [CAShapeLayer layer];
        shapeLayer.path = [path CGPath];
        shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
        shapeLayer.lineWidth = 3.0;
        shapeLayer.fillColor = [[UIColor redColor] CGColor];
        [drawingView.layer addSublayer:shapeLayer];
    }
    startingPoint=touchPoint;

//    [arrLayer addObject:shapeLayer];
    NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
{
    startingPoint = CGPointZero;
}


@end